PTERXS. 
175 
times ; it is found in the Yorkshire dales and elsewhere, 
and forms a good variety for ferneries. 
Var. polyschides has very narrow fronds, occasionally 
becoming so deeply lobed as to be pinnatifid. It is 
found near Bristol. 
Var. lobatum has the frond only once forked. 
Yar. ramosum is forked from the stem. 
Var. cristatum has the points of the frond crested. 
There are two varieties known in ferneries, of very pe- 
culiar appearance. One is called var. proliferum , and 
has very small fronds, with extremely little leafy expan- 
sions ; and the other, foecundum , produces young plants 
on the fronds. 
Yar. undulatum is another form of crispum. 
The Hart's-tongue grows abundantly in the British 
Isles, and also over Europe, in the Caucasus ; according 
to Hooker, it is a rare fern in the United States. 
FTEBIS. 
38. Fteris aquilina, Linn. Common Brake. 
Candex long and wide-spreading. Stem erect, tawny. Fronds 
large, somewhat triangular, tough, tripinnate. Leaflets sessile, 
narrow, entire. Sori in a line on the margin. Involucre formed 
of the margin of the frond turned hack over the sori. 
Name from pteron, Greek for feather. 
The roots of the Common Brake are fibrous and 
downy • the caudex brown, velvety, and far-spreading ; 
the frond is bipinnate or tripinnate, in sterile soil tri- 
angular and three-branched, but lanceolate, triangular 
in favourable situations. The pinnae are opposite ; the 
leaflets ovate, elongated, sessile, and undivided, some- 
times waved at the margin ; the sori are situated on a 
